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Topic: Oxidation of alfa,gamma-diols  (Read 3929 times)

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Oxidation of alfa,gamma-diols
« on: March 23, 2006, 11:00:10 AM »
Hello!

I need to oxidate 1,3-propanediol to hydroxyaldehyde? I tried cyclohexanone with Cp2ZrH2(cat.), 150', it didn't worked. Obviously monoprotection and selective oxidation is required. Could somebody give any suggestions about protecting group/oxidant?

Thank you.

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Re:Oxidation of alfa,gamma-diols
« Reply #1 on: March 23, 2006, 12:15:33 PM »
A benzyl ether would be a good one.  It's easy to put on one hydroxyl selectively if you use NaH and 1 equiv of BnBr.  Then, you can oxidize the remaining alcohol with any of a number of oxidants, PCC for example.

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Re:Oxidation of alfa,gamma-diols
« Reply #2 on: March 24, 2006, 08:57:22 AM »
Thanks!

I already have it monoprotected with TBDMS. Do you think it can withstand PCC-oxidation?
 
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Re:Oxidation of alfa,gamma-diols
« Reply #3 on: March 24, 2006, 12:21:16 PM »
Yeah, that should be okay.  If you're really worried about it, there are plenty of other oxidation options: Swern, Dess-Martin, TPAP/NMO....

All of those would be fine with a TBDMS group.

In your case, there is the possibility of beta-elimination to form acrolein.  You might want to consider Dess-Martin reagent because it is probably the most mild oxidant of the ones that I mentioned, so beta-elimination would be minimized.
« Last Edit: March 24, 2006, 12:22:49 PM by movies »

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